The plating is a knitting technique of knitting a knitted fabric in such a manner that a front yarn and a back yarn are both fed to knitting needles so that the front yarn can come to the front side of the front stitch formed and also the back yarn can come to the back side (the reverse side) of the front stitch so that the back yarn can be enfolded by the front yarn. The back yarn comes to the front side of back stitch formed and also the front yarn is hidden behind the back side (the reverse side) thereof. Due to this, the plating requires that the back yarn be located nearer to a hook side than the front yarn. For this, the plating is carried out, for example, by using both a front-yarn yarn feeder and a back-yarn yarn feeder and driving them in such a timed sequence that the front-yarn yarn feeder is driven ahead of the back-yarn feeder, or by using a yarn feeding device having two yarn feeders different in position and level or by using a yarn feeder capable of turning in response to change in a traveling direction of a carriage (cf. International Publication Pamphlet of International Publication No. WO01/064988, for example). The plating is also used for producing a reversible knitted fabric.
However, this conventional plating involves the following problems when a tubular knitted fabric, such as knitwear of a wide rib structure whose front and back knitted fabrics are joined to each other at lateral sides thereof and in which a number of front stitches and back stitches come out alternately by the plating, is knitted using a flat knitting machine. It is to be noted that the term of “the tubular knitted fabric” used in this specification is intended to cover not only a complete tubular knitted fabric extending continuously over the entire knitting width, but also a C-shaped tubular knitted fabric or a separated tubular knitted fabric, like a cardigan.
Japanese Patent Gazette of Patent No. 3121283 refers to a crossing of the knitting yarns which occurs when the tubular knitted fabric is knitted by a 2-system knitting using two yarn feeders. The same is true of the case where the tubular knitted fabric is knitted by the plating. In the plating, the front yarn must be always fed to the needles ahead of the back yarn, but in the flat knitting machine, the yarn feeders are reversed in knitting direction at opposite ends of the knitting width of the tubular knitted fabric, so that the crossing of the front yarn and the back yarn occurs at any one end of the knitting width. When the next stitch is formed in the state of the front yarn and the back yarn being reversed in position for a moment by the crossing, the yarn which really should not come out comes to the front side, causing blur (color mixing) of the knitted fabric at lateral ends thereof and thus reducing the commercial value of the knitwear. In the plating using the flat knitting machine, such a crossing of the knitting yarns cannot be avoided. Due to this, when the tubular knitted fabric is knitted using the flat knitting machine, the plating has been avoided so far. Irrespective of the types of yarn feeder and the number of needle beds of the flat knitting machine, the crossing occurs,